ORLAND (KPIX 5) — The fire that claimed most of the lives in the fatal chain reaction crash between a FedEx truck and a charter bus Thursday night may have started before the big rig collided with them, according to key witnesses.

Flames were visible as the truck careened head-on into the bus, according to Bonnie Duran, whose vehicle was the first to be hit by the truck before it hit a bus load of low-income high school seniors heading to a college preview event at Humboldt State University.

Ten people died in the wreck including students, chaperones, and both drivers. A total of 48 were injured.

“I was heading along the outside lane. And I looked over and saw the FedEx truck coming right for me and it was on fire already,” Duran told KPIX 5’s Brian Webb.

Her husband Joe says they couldn’t get out of the way, “It was like a 3D movie– you see a Mack truck coming at you. It was unbelievable. We didn’t even gave time to react.”

Investigators believe the FedEx truck crossed to the wrong side of the highway, and clipped the Duran’s rental car before heading at full speed for the bus filled with over 40 college students and their chaperones.

The Durans insist the FedEx truck was already on fire when they first spotted it.

It took 20 hours to remove the burned debris from the highway, but Interstate 5 is back open even as the investigation continues.

The National Transportation Safety Board will now look at everything from evidence at the crash site to what each driver was doing in the 72 hours before the crash.